Describing huckel rule and its limitations

Question

Answer the following questions.

Question 1) Describe Huckel’s rule and its limitations. Explain the modern concept of aromaticity with appropriate examples.

Question 2) Write a detail note on the following:

(i) Alternant and non-alternant hydrocarbons,

(ii) Aromatic character of azulenes.

Question 3) Explain optical activity of allenes.

Question 4) Describe the terms stereo specific and stereo selective synthesis with appropriate examples.

Question 5) What is asymmetric synthesis? Explain the asymmetric synthesis using a chiral catalyst.

Question 6) Describe why trans –1, 3-di-t-butyl cyclohexane prefers a boat conformation.

Question 7) Write a short explanatory notes on the following:

(i) Kinetically and thermodynamically controlled products,

(ii) Isotopic Labelling.

Question 8) Explain the formation and reactions of carbenes.

Question 9) Describe neighbouring group participation with appropriate examples.

Question 10) Describe different factors that influence the nucleophilic substitution reaction to proceed by either SN¹ mechanism or SN² mechanism.